Where not in and Where "Or" problem

public class ClassEntityA
{
    public int Id { get; set; }
    public string Text { get; set; }
}

public class ClassEntityB
{
    public int Id { get; set; }
    public string Text { get; set; }
    public Nullable EntityA { get; set; }
}


// I need to do the following query in Ado Entity. That query works in Linq To Sql, but not suported in Linq To Entity

list<int> list = new List<in>() { 1, 2, 3 };
var itens = DbContext.ClassEntityB.Where(c => (list.Contains(c.EntityA.Id) ==  false || c.EntityA == null);

// i Found a Half Solution to do that in Linq To Entity doing that:

// But Here i can do the second test (OR c.EntityA == null). How can i do That?

list<int> list = new List<in>() { 1, 2, 3 };
var itens = DbEntities.ClassEntityB.WhereNotIn(c => c.EntityA.Id, list.AsEnumerable<int>())


 #region Where Not In

        private static Expressionbool>>
            GetWhereNotInExpression(
            Expression> propertySelector,
            IEnumerable values)
        {
            ParameterExpression p =
                propertySelector.Parameters.Single();

            if (!values.Any())
            {
                return e => true;
            }

            var unequals = values.Select(value =>
                (Expression)Expression.NotEqual(
                    propertySelector.Body,
                    Expression.Constant(value, typeof(TValue))
                )
            );

            var body = unequals.Aggregate(
                (accumulate, unequal) => Expression.And(accumulate, unequal));

            return Expression.Lambdabool>>(body, p);
        }

        public static IQueryable
            WhereNotIn(this IQueryable source,
            Expression> propertySelector,
            params TValue[] values)
        {
            return source.Where(GetWhereNotInExpression(
                propertySelector, values));
        }

        public static IQueryable
            WhereNotIn(this IQueryable source,
            Expression> propertySelector,
            IEnumerable values)
        {
            return source.Where(GetWhereNotInExpression(
                propertySelector, values));
        }

        #endregion